Filament, method for producing filament, method for producing ceramic matrix composite precursor, and method for producing ceramic matrix composite

Abstract

The purpose of the present invention is to provide at least one of: a filament which can be used in the production of a CMC by means of 3D print modeling, and which satisfies at least either a compound containing ceramic particles and an organic binder is not likely to be separated from a ceramic continuous fiber, or a CMC obtained from the filament exhibits a high tensile strength; a method for producing the filament; a method for producing a CMC precursor using the filament; and a method for producing a CMC using the CMC precursor.　Provided is a filament which contains ceramic particles, an organic binder, and a ceramic continuous fiber, wherein the area ratio of the cross-sectional area of the ceramic continuous fiber to the cross-sectional area of the filament is 15 area% or more.

Description

Filament, method for manufacturing filament, method for manufacturing ceramic matrix composite precursor, and method for manufacturing ceramic matrix composite

[0001] The present disclosure relates to filaments, methods for making filaments, methods for making ceramic matrix composite precursors, and methods for making ceramic matrix composites.

[0002] Ceramic matrix composites (hereinafter also referred to as "CMCs"), which combine continuous ceramic fibers with a ceramic matrix, are more resistant to fracture of the entire material due to the progression of flaws than ordinary ceramics. For this reason, CMCs are being studied as a substitute for heat-resistant metals such as nickel (Ni)-based alloys, and are expected to be used as components for aircraft jet engines, for example.

[0003] Furthermore, in order to produce CMCs having three-dimensional structures with complex shapes, the production of CMCs by 3D printing has been considered. For example, Non-Patent Document 1 discloses the production of CMCs by 3D printing. Specifically, it discloses the steps of combining a compound containing resin and alumina powder with alumina continuous fibers to produce an alumina filament containing alumina continuous fibers, printing the produced filament using a fused deposition modeling (FDM) method in a 3D printer to obtain a shaped object, and heating the obtained shaped object in an electric furnace to debinder and sinter it.

[0004] Proceedings of the 2024 Annual Meeting of the Ceramic Society of Japan, Naoya Hagiwara, Yutaro Arai, Ryo Inoue, Ryosuke Matsuzaki, Hideki Kakizawa, Kazuya Shimoda

[0005] In Non-Patent Document 1, a compound containing alumina particles and a resin, and a filament containing continuous ceramic fibers are used as raw materials in the production of a CMC by 3D printing. However, the filament in Non-Patent Document 1 was prone to peeling of the compound from the continuous ceramic fibers, and the resulting CMC had low tensile strength.

[0006] The present disclosure aims to provide a filament that can be used to produce a CMC by 3D printing, which satisfies at least one of the following: a compound containing ceramic particles and an organic binder is not easily peeled off from the ceramic continuous fiber; and a CMC obtained from the filament exhibits high tensile strength; and a method for producing the filament; a method for producing a CMC precursor using the filament; and a method for producing a CMC using the CMC precursor.

[0007] The present inventors conducted research into the relationship between continuous ceramic fibers and compounds in filaments, which are raw materials for manufacturing CMCs by 3D printing. As a result, they discovered that the proportion of continuous ceramic fibers contained in a filament affects at least one of the ease with which the compound peels from the continuous ceramic fibers and the tensile strength of a CMC manufactured from the filament by 3D printing, and arrived at the present disclosure.

[0008] That is, the present invention is as defined in the claims, and the gist of the present disclosure is as follows. [1] A filament comprising ceramic particles, an organic binder, and a ceramic continuous fiber, wherein the area ratio of the cross-sectional area of ​​the ceramic continuous fiber to the cross-sectional area of ​​the filament is 15 area % or more. [2] The filament according to [1] above, wherein the ceramic particles are one or more particles selected from the group consisting of alumina particles, mullite particles, silica particles, and zirconia particles. [3] The filament according to [1] or [2] above, wherein the ceramic continuous fiber is one or more particles selected from the group consisting of alumina continuous fiber, mullite continuous fiber, and alumina and mullite mixed continuous fiber. [4] The ceramic continuous fiber has a crystal structure of an α-alumina structure and a mullite structure, and further contains Al ２ O ３

[0013] The filament according to any one of [1] to [3] above, wherein the content is 80% by mass or more and less than 100% by mass. [5] The filament according to any one of [1] to [4] above, wherein the area ratio of the cross-sectional area of ​​the void portion to the cross-sectional area of ​​the filament is less than 19% by area. [6] The filament according to any one of [1] to [5] above, wherein the volume ratio of the ceramic particles to the total volume of the ceramic particles and the organic binder is 35% by volume or more and 60% by volume or less. [7] The filament according to any one of [1] to [6] above, wherein the ceramic continuous fiber is composed of 100 or more single fibers. [8] The filament according to any one of [1] to [7] above, wherein the filament is for 3D printing. [9] A method for producing the filament according to any one of [1] to [8] above, comprising: bringing a resin composition containing the ceramic particles and the organic binder, which has been heated at the following heating temperature, into contact with the ceramic continuous fiber; and passing the resin composition and the ceramic continuous fiber that have been brought into contact with each other through a spinning hole.

[10] The method according to [9] above, wherein the diameter of the spinning hole is less than 0.6 mm.

[11] A method for producing a ceramic matrix composite precursor, which comprises heating the filament according to any one of [1] to [8] above to melt the organic binder, and then 3D printing the filament.

[12] A method for producing a ceramic matrix composite material, which comprises firing the ceramic matrix composite precursor obtained by the method according to

[11] above.

[0009] The present disclosure provides a filament that can be used to produce a CMC by 3D printing, which satisfies at least one of the following: a compound containing ceramic particles and an organic binder is not easily peeled off from the ceramic continuous fiber; and a CMC obtained from the filament exhibits high tensile strength; a method for producing the filament; a method for producing a CMC precursor using the filament; and a method for producing a CMC using the CMC precursor.

[0010] Fig. 1 is a schematic diagram of an apparatus used to produce a filament of the present disclosure. Fig. 2 is a cross-sectional observation image of a filament produced in Example 2 (magnification: 300x). Fig. 3 is an external view of the filament produced in Example 2. Fig. 4 is an external view of the filament produced in Comparative Example 1. Fig. 5 is a schematic diagram showing a test specimen used to measure the tensile strength of a CMC having a crack at the strength retention rate.

[0011] The filaments of the present disclosure will be described with reference to an example embodiment. The terms used in this embodiment are as follows. The present disclosure also includes any combination of the configurations and parameters disclosed herein, as well as any combination of the upper and lower limits of the values ​​disclosed herein.

[0012] A "ceramic matrix composite" (CMC) is a material in which ceramic continuous fibers and a ceramic matrix are combined, and is a so-called ceramic fiber reinforced ceramic.

[0013] The term "ceramic matrix" refers to a ceramic that serves as the matrix (parent phase) of a CMC, and is essentially a matrix (parent phase) of a CMC that is composed of ceramic crystal particles (hereinafter also referred to as "crystal particles").

[0014] "Ceramic fiber" refers to a spun polycrystalline ceramic, or even a filamentous polycrystalline ceramic, and is a fiber composed of crystal particles. Ceramic fibers are classified into "ceramic short fiber" and "ceramic continuous fiber" depending on their fiber length. In this embodiment, "ceramic short fiber" refers to a ceramic fiber with a fiber length of less than 10 cm, and "ceramic continuous fiber" refers to a ceramic fiber other than ceramic short fiber (ceramic fiber with a fiber length of 10 cm or more). Furthermore, "ceramic mixed fiber" refers to a ceramic fiber having a mixed structure of crystal particles of two or more types of ceramics, and "ceramic mixed continuous fiber" refers to a ceramic continuous fiber having a mixed structure of crystal particles of two or more types of ceramics.

[0015] A "fiber bundle" is an assembly of two or more single fibers.

[0016] A "filament" is a thread-like structure, and further, a thread-like formed body.

[0017] The term "ceramic particles" refers to fine particles containing ceramic as a main component, and further refers to fine particles made of ceramic. In this embodiment, the ceramic particles are preferably powder particles.

[0018] "Average particle size" refers to the median diameter (D) in the volume particle size distribution of a powder measured by a wet method. ５０ The "average particle size" can be measured using a general laser diffraction / scattering particle size distribution measuring device (for example, MT3300EX-II, manufactured by Microtrackbell) under the following conditions:

[0019] Light source: Semiconductor laser Voltage: 780mW Refractive index of solvent (water): 1.333 Calculation mode: MT3000EXII

[0020] The measurement sample may be prepared by dispersing particles, from which slow aggregation has been removed by a dispersion treatment such as ultrasonication, in pure water to form a slurry.

[0021] The "fiber content" is the area ratio of the cross-sectional area of ​​the ceramic continuous fiber to the cross-sectional area of ​​the filament. The "fiber content" can be determined by analyzing a cross-sectional image of the filament obtained with a general digital microscope (for example, VHX-6000, manufactured by Keyence) using general image analysis software (for example, Nanohunter, manufactured by NanoSystems), and can be determined under the following measurement conditions.

[0022] Observation magnification: 200x or 300x Pixels: 1600 x 1200 pixels

[0023] Prior to the measurement, the measurement sample may be prepared by cutting the filament, embedding the cut surface in a resin so that the cut surface is exposed on the surface, and then polishing the surface including the cut surface using a general manual polishing machine (e.g., EcoMet 30, manufactured by Buhler).

[0024] In image analysis, a cross-sectional observation image of the filament is imported into image analysis software, and the diameter of the circle equivalent to the area of ​​the periphery of the filament is taken as the diameter of the filament. Similarly, the diameter of the circle equivalent to the area of ​​the periphery of the continuous ceramic fiber is taken as the diameter of the continuous ceramic fiber. However, if the continuous ceramic fiber is composed of multiple monofilaments, the diameter of the circle equivalent to the area of ​​the periphery of a monofilament of the continuous ceramic fiber is taken as the diameter of the monofilament of the continuous ceramic fiber. In addition, the number of monofilament continuous ceramic fibers contained in the filament is calculated using image analysis software. The area-equivalent circle should be created so that the portion of the filament or continuous ceramic fiber outside the area-equivalent circle is minimized.

[0025] When the ceramic continuous fiber is composed of a plurality of single fibers, the fiber content can be calculated using the filament diameter calculated by image analysis, the diameter of the single fiber of the ceramic continuous fiber, and the number of single fibers of the ceramic continuous fiber, and the following formula.

[0026] Cross-sectional area of ​​the filament (μm ２ ) = {filament diameter (μm) / 2} ２ ×π Cross-sectional area of ​​ceramic continuous fiber (μm ２) = {diameter of single ceramic continuous fiber (μm) / 2} ２ × π × (number of single fibers of ceramic continuous fiber) Fiber content (area %) = Cross-sectional area of ​​ceramic continuous fiber (μm ２ ) / cross-sectional area of ​​filament (μm ２ ) x 100

[0027] When the ceramic continuous fiber is composed of one single fiber, the fiber content can be calculated using the filament diameter calculated by image analysis and the diameter of the single fiber of the ceramic continuous fiber, using the following formula.

[0028] Cross-sectional area of ​​the filament (μm ２ ) = {filament diameter (μm) / 2} ２ ×π Cross-sectional area of ​​ceramic continuous fiber (μm ２ ) = {diameter of single ceramic continuous fiber (μm) / 2} ２ ×π Fiber content (area%) = Cross-sectional area of ​​ceramic continuous fiber (μm ２ ) / cross-sectional area of ​​filament (μm ２ ) x 100

[0029] The "void ratio" is the area ratio of the cross-sectional area of ​​the void portion to the cross-sectional area of ​​the filament, and can be determined by using a cross-sectional observation image of the filament created when determining the fiber content and performing image analysis using general image analysis software (e.g., Nanohunter, manufactured by NanoSystems), and can be determined by the following method.

[0030] First, the cross-sectional observation image of the filament is imported into image analysis software, and a circle equivalent to the area of ​​the outer periphery of the filament is created. The circle equivalent to the area is created so that the portion of the filament outside the circle equivalent to the area is minimized. Using the image analysis software, the circle equivalent to the area is converted to 8-bit black and white and converted into a grayscale image.

[0031] Next, the grayscale image is binarized using a threshold value of 110 to obtain a binary image. The obtained binary image is subjected to black-and-white inversion processing to obtain a processed image in which voids are white and filaments are black. Noise in the processed image can be removed using the hole filling function and isolated point removal function of the image processing software.

[0032] Using image analysis software, the area of ​​the white portions (void portions) in the obtained processed image is determined, and then the ratio (area %) of the area of ​​the white portions to the cross-sectional area of ​​the filament is calculated, and this value can be used as the void ratio.

[0033] The "tensile strength A" of a CMC is a value determined by a method conforming to JIS R 1656 using a general strength testing machine (for example, AG-50kN Xplus, manufactured by Shimadzu Corporation) and a tensile testing jig. The measurement sample may be a CMC processed to a width of 10±1 mm, length of 60±10 mm, and thickness of 1.2±0.6 mm, with epoxy glass tabs attached to both ends. The loading rate may be 1 mm / min.

[0034] The "tensile strength B" of a CMC is a value determined using a general strength testing machine (e.g., MTS Criterion, manufactured by MTS) and a tensile test jig according to a method conforming to ASTM C1275. The tensile strength is measured twice at a loading rate of 0.5 mm / min, and the average value of the values ​​obtained is taken as the tensile strength B. The measurement sample may be a CMC processed to a width of 10±1 mm, a length of 100±10 mm, and a thickness of 1.2±0.6 mm, with aluminum tabs attached to both ends.

[0035] The "flow initiation temperature" is the temperature at which a piston begins to move from its position at the softening temperature when a sample is packed into a thermal flow evaluation device and heated while applying a constant load with a piston to soften the sample. This temperature can be determined under the following measurement conditions using a general thermal flow evaluation device conforming to JIS K 7210 (for example, CFT-500D, manufactured by Shimadzu Corporation).

[0036] Test temperature: 40°C to 250°C Heating rate: 5°C / min Applied pressure: 0.49 MPa Applied load: 5 kg Preheating time: 300 seconds Cylinder inner diameter: 11.3 mm (cross-sectional area: 1 cm ２ ) Piston outer diameter: 11.3mm (cross-sectional area: 1cm ２ ) Capillary die: A capillary die having a die with a cylindrical hole having a length of 1 mm and an inner diameter of 0.5 mm.

[0037] The "fiber volume fraction" of a CMC is the volume fraction [volume %] of ceramic continuous fibers in the CMC, and is a value determined from a cross-sectional observation diagram of the CMC. ｆ In the measurement of ), a cross-sectional observation image of the CMC is obtained using a general digital microscope (for example, VHX-6000, manufactured by Keyence) with the image stitching function attached to the digital microscope under the following conditions: Observation magnification: 500 times Observation field of view: 20±1 mm × 9±1 mm

[0038] Prior to the measurement, the CMC sample is cut into a plate having a width of 10±1 mm and a length of 10±1 mm, embedded in a resin so that the cut surface is exposed on the surface, and then polished with a general manual polishing machine (for example, EcoMet 30, manufactured by Buhler) to polish the surface including the cut surface.

[0039] A cross-sectional observation image of the CMC can be binarized using general image analysis software (e.g., Nanohunter, manufactured by Nanosystems), and the fiber volume fraction can be determined by analyzing the resulting binarized image. The fiber volume fraction can be determined from the following formula, regarding the white areas in the binarized image as continuous ceramic fibers and the black areas in the binarized image as ceramic matrix. V ｆ = A ｆ / (A ｆ +A ｍ ) × 100 In the above formula, V ｆ is the fiber volume fraction (volume%), A ｆ is the area of ​​the ceramic continuous fiber (mm ２ ), A ｍis the area of ​​the ceramic matrix (mm ２ )

[0040] <<Filament>> The filament of the present embodiment is a filament containing ceramic particles, an organic binder, and continuous ceramic fibers, and the area ratio of the cross-sectional area of ​​the continuous ceramic fibers to the cross-sectional area of ​​the filament is 15 area % or more.

[0041] In the filament of this embodiment, the area ratio of the cross-sectional area of ​​the continuous ceramic fiber to the cross-sectional area of ​​the filament (hereinafter also referred to as the "fiber content") is 15 area% or more. This ensures that at least one of the following is achieved: the resin composition containing ceramic particles and an organic binder (hereinafter also referred to as the "compound") does not peel off from the continuous ceramic fiber; and the CMC obtained from the filament exhibits high tensile strength. If the fiber content is less than 15 area%, the interfacial strength between the continuous ceramic fiber and the ceramic matrix in the CMC obtained by 3D printing is reduced, the progression of scratches is not suppressed, and the tensile strength of the CMC is reduced. Furthermore, if the fiber content is less than 15 area%, the compound is present in excess in the filament, which may clog the nozzle of the 3D printing device during 3D printing. Furthermore, satisfying the above-mentioned fiber content of the filament is thought to thin the layer of the compound containing ceramic particles and an organic binder, thereby preventing the compound layer from peeling off from the continuous ceramic fiber.

[0042] The fiber content is preferably greater than 15 area%, 17 area% or more, 20 area% or more, 25 area% or more, 30 area% or more, or even 40 area% or more, since this tends to increase the tensile strength of the resulting CMC. A higher fiber content is preferable, but the upper limit may be 70 area% or less, 65 area% or less, 60 area% or less, 55 area% or less, or 50 area% or less. The fiber content may also be 15 area% or more and 70 area% or less, greater than 15 area% and 70 area% or less, 20 area% or more and 65 area% or less, 25 area% or more and 60 area% or less, 25 area% or more and 55 area% or less, 25 area% or more and 50 area% or less, 30 area% or more and 50 area% or less, or 40 area% or more and 55 area% or less. The volume ratio of the ceramic continuous fiber to the volume of the filament is the same as the fiber content.

[0043] The filament of this embodiment may have a porosity of less than 19 area%, 17 area% or less, 15 area% or less, or 12 area% or less. A smaller porosity is preferable, and examples of the lower limit include 1 area% or more, 2 area% or more, 3 area% or more, or 5 area% or more. The porosity may be 1 area% or more but less than 19%, 2 area% or more to 17 area% or less, 3 area% or more to 15 area% or less, or 5 area% or more to 12 area% or less.

[0044] The diameter of the filament in this embodiment (hereinafter also referred to as "filament diameter") may be 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, or 0.4 mm or more, or 5.0 mm or less, 4.0 mm or less, 3.0 mm or less, 2.0 mm or less, or 1.0 mm or less. Furthermore, the filament diameter in this embodiment may be 0.1 mm or more and 5.0 mm or less, 0.2 mm or more and 4.0 mm or less, 0.3 mm or more and 3.0 mm or less, 0.4 mm or more and 2.0 mm or less, or 0.4 mm or more and 1.0 mm or less.

[0045] The filament diameter can be determined by analyzing a cross-sectional view of the filament obtained with a general digital microscope (for example, VHX-6000, manufactured by Keyence) using general image analysis software (for example, Nanohunter, manufactured by NanoSystems). The following measurement and analysis conditions can be used.

[0046] Observation magnification: 200x or 300x Pixels: 1600 x 1200 pixels

[0047] Prior to the measurement, the measurement sample may be prepared by cutting the filament in a direction perpendicular to the longitudinal direction of the filament to obtain a cut surface, embedding the cut surface in a resin so that the cut surface is exposed on the surface, and then polishing the surface using a general manual polishing machine (e.g., EcoMet 30, manufactured by Buehler).

[0048] For image analysis, the cross-sectional observation image of the filament is imported into image analysis software, and the diameter of the circle equivalent to the area of ​​the outer periphery of the filament is taken as the filament diameter. The circle equivalent to the area should be created so that the portion of the filament outside the circle equivalent to the area is minimized.

[0049] In this embodiment, the length of the filament may be 10 cm or more, 1 m or more, 2 m or more, 5 m or more, 10 m or more, 50 m or more, or 100 m or more, or 10,000 m or less, 8,000 m or less, 5,000 m or less, 1,000 m or less, 500 m or less, 100 m or less, 50 m or less, or 10 m or less. In addition, the length of the filament in this embodiment may be 10 cm or more to 10,000 m or less, 1 m or more to 5,000 m or less, 1 m or more to 500 m or less, or 50 m or more to 100 m or less.

[0050] In the filament of this embodiment, at least a portion of the periphery of the continuous ceramic fiber is coated with a resin composition containing ceramic particles and an organic binder, and preferably the periphery of the continuous ceramic fiber is entirely coated with a compound. When the periphery of the continuous ceramic fiber is coated with a compound, it becomes easier to obtain a 3D printed object in the desired shape.

[0051] The filament of this embodiment has, for example, few cracks in the compound, or even no cracks in the compound. This makes the filament less likely to break when fed to a 3D printing device. Furthermore, the filament of this embodiment can be more easily wound onto a bobbin or the like.

[0052] (Ceramic Particles) In this embodiment, the ceramic particles can be, for example, at least one of powder particles and colloidal particles, and are preferably powder particles.

[0053] The ceramic constituting the ceramic particles is at least one of oxide ceramics and non-oxide ceramics, and is preferably oxide ceramics, and alumina (Al ２ O ３ ), mullite (3Al ２ O ３ 2SiO ２ ), silica (SiO ２ ), and zirconia (ZrO ２ ) is more preferably one or more selected from the group consisting of alumina, mullite and zirconia, still more preferably at least one of alumina and mullite, and preferably contains at least alumina.

[0054] The zirconia constituting the ceramic particles is zirconia in which a stabilizing element is dissolved, preferably zirconia in which yttrium is dissolved, more preferably Y ２ O ３ Zirconia in which yttrium is dissolved in a solid solution of 2.0 mol % or more and 4.0 mol % or less in terms of Y ２ O ３ It may be zirconia in which 2.5 mol % or more and 3.5 mol % or less of yttrium is dissolved in solid form.

[0055] Specific ceramic particles are preferably one or more types selected from the group consisting of alumina particles, mullite particles, silica particles, and zirconia particles, more preferably one or more types selected from the group consisting of alumina particles, mullite particles, and zirconia particles, further preferably at least one of alumina particles and mullite particles, and preferably contain at least alumina particles.

[0056] The ceramic particles may be one or more types selected from the group consisting of alumina powder particles, mullite powder particles, silica powder particles, and zirconia powder particles. Preferably, the ceramic particles are one or more types selected from the group consisting of alumina powder particles, mullite powder particles, and zirconia powder particles, or at least either alumina powder particles or mullite powder particles, or further preferably include at least alumina powder particles, and more preferably are alumina powder particles.

[0057] The ceramic constituting the ceramic particles is preferably alumina, since this increases the strength of the resulting CMC. Also, the ceramic constituting the ceramic particles is preferably at least one of alumina and mullite, more preferably mullite, since this increases the heat resistance of the resulting CMC.

[0058] The average particle size of the ceramic particles may be 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more, or may be less than 10 μm, 8 μm or less, 5 μm or less, 3 μm or less, or 1 μm or less. Furthermore, the average particle size of the ceramic particles is preferably 0.05 μm or more and less than 10 μm, 0.05 μm or more and 5 μm or less, 0.05 μm or more and 3 μm or less, 0.1 μm or more and 3 μm or less, or 0.1 μm or more and 1 μm or less. Having the average particle size of the ceramic particles within the above range makes it easier to uniformly disperse the ceramic particles around the continuous ceramic fiber.

[0059] (Additive Source) The filament of this embodiment contains ceramic particles, an organic binder, and continuous ceramic fibers, and may consist of ceramic particles, an organic binder, and continuous ceramic fibers, but may also contain an additive source in addition to the ceramic particles, the organic binder, and continuous ceramic fibers, and preferably contains a substance that has the function of suppressing grain growth of the ceramic particles during heat treatment.

[0060] The additive source may be a compound having a different composition from the ceramic particles. ２ ), zirconia (ZrO ２ ), yttria (Y ２ O ３ ), ytterbium oxide (Yb ２ O ３ ), and mullite (3Al ２ O ３ 2SiO ２ ) can be exemplified as one or more selected from the group consisting of silica, zirconia, mullite, and ytterbium oxide, and more preferably one or more selected from the group consisting of silica, zirconia, and mullite. Since the tensile strength of the resulting CMC tends to be high, the additive source preferably contains at least silica, and more preferably silica and zirconia. The zirconia contained as the additive source is zirconia in which yttrium is solid-dissolved, preferably Y ２ O ３ Zirconia in which yttrium is dissolved in a solid solution of 2.0 mol % or more and 4.0 mol % or less in terms of yttrium conversion, more preferably Y ２ O ３ It is sufficient if the zirconia contains 2.5 mol % or more and 3.5 mol % or less of yttrium in solid solution.

[0061] In this embodiment, the additive source can be, for example, at least one of powder particles and colloidal particles, and is preferably powder particles.

[0062] The average particle size of the additive source may be 0.005 μm or more, 0.01 μm or more, 0.02 μm or more, or 0.05 μm or more, or may be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Furthermore, the average particle size of the additive source is preferably 0.005 μm or more and less than 10 μm, 0.01 μm or more and 5 μm or less, 0.02 μm or more and 3 μm or less, 0.05 μm or more and 2 μm or less, or 0.05 μm or more and 1 μm or less. Having the average particle size of the additive source within the above range makes it easier to uniformly disperse the additive source in the compound.

[0063] The filament of this embodiment may contain one or more and five or less, one or more and three or less, one or more and two or less, or one or more additive sources.

[0064] In the filament of this embodiment, the mass ratio of the additive source to the mass of the filament (hereinafter also referred to as the "additive source amount") is 0.1 mass% or more, 0.2 mass% or more, or 0.3 mass% or more, and 4.7 mass% or less, 4.5 mass% or less, or 4.0 mass% or less. Examples of the additive source amount are 0.1 mass% or more and 4.7 mass% or less, 0.2 mass% or more and 4.5 mass% or less, or 0.3 mass% or more and 4.0 mass% or less. When the additive source amount is in the above range, it becomes easier to uniformly disperse the additive source in the compound.

[0065] (Continuous Ceramic Fiber) In this embodiment, the continuous ceramic fiber is included in the filament.

[0066] The ceramic continuous fiber is not particularly limited as long as it is a ceramic continuous fiber made of ceramic, and examples of the ceramic continuous fiber contained in the filament of this embodiment include ceramic continuous fibers containing one or more selected from the group consisting of silicon carbide, alumina, and mullite (hereinafter, ceramic continuous fibers made of alumina, etc., are also referred to as "alumina continuous fibers," etc.), with ceramic continuous fibers containing at least one of alumina and mullite being preferred. Specific ceramic continuous fibers include one or more selected from the group consisting of silicon carbide continuous fiber, alumina continuous fiber, mullite continuous fiber, and alumina and mullite mixed continuous fiber, further including one or more selected from the group consisting of alumina continuous fiber, mullite continuous fiber, and alumina and mullite mixed continuous fiber, and further including at least one of alumina continuous fiber and alumina and mullite mixed continuous fiber.

[0067] Preferably, the ceramic continuous fibers are alumina continuous fibers, since the resulting CMC exhibits higher tensile strength.

[0068] In order for the resulting CMC to exhibit higher heat resistance, the ceramic continuous fiber is preferably one or more selected from the group consisting of alumina continuous fiber, mullite continuous fiber, and alumina and mullite mixed continuous fiber, and more preferably alumina and mullite mixed continuous fiber.

[0069] A preferred alumina continuous fiber is one having an α-alumina structure in its crystal structure and containing Al ２ O ３ A ceramic continuous fiber having a content of 60 mass % or more and 100 mass % or less, or a ceramic continuous fiber having an α-alumina structure in its crystal structure and containing Al ２ O ３ Examples of the ceramic continuous fibers include those having a content of 80% by mass or more and less than 100% by mass.

[0070] A preferred alumina and mullite mixed continuous fiber is one having a crystal structure of α-alumina and mullite, and further having Al ２ O ３Ceramic continuous fibers having a content of 80% by mass or more and less than 100% by mass, and further having a crystal structure of an α-alumina structure and a mullite structure, and further having an Al ２ O ３ The content is 80% by mass or more and 95% by mass or less, and SiO ２ Examples of the ceramic continuous fibers include those having a content of more than 5% by mass and less than 20% by mass.

[0071] In the ceramic continuous fiber, the crystal structure of at least one of an α-alumina structure and a mullite structure can be confirmed by detecting an XRD peak derived from at least one of α-alumina and mullite in XRD measurement and analysis of the XRD pattern. XRD peaks derived from at least one of α-alumina and mullite can be found by referring to a general database (for example, PDF (Powder Diffraction File) 2, manufactured by the International Centre for Diffraction Data).

[0072] The XRD pattern can be measured using a general X-ray diffractometer (for example, Ultima IV, manufactured by RIGAKU Corporation). The measurement conditions include the following:

[0073] Radiation source: CuKα ray (λ = 0.15418 nm) Measurement mode: Continuous scan Scan speed: 2° / min Measurement range: 2θ = 10° to 80° Acceleration voltage / current: 40 mA / 40 kV Divergence vertical limiting slit: 10 mm Divergence / entrance slit: 1° Receiving slit: open Detector: Semiconductor detector (D / teX Ultra) Filter: Ni filter Goniometer radius: 185 mm

[0074] After measurement under the above measurement conditions, analysis can be performed using an analysis program attached to the X-ray diffractometer (for example, integrated powder X-ray analysis software PDXL Ver. 2.2, manufactured by RIGAKU Corporation). The analysis conditions include the following:

[0075] Peak shape: Split pseudo-Voigt function Background processing: Straight line connecting the endpoints

[0076] In ceramic continuous fibers, Al ２ O ３ Content, or SiO ２ The content can be determined using a general X-ray fluorescence analyzer (for example, ZSM Primus II, manufactured by RIGAKU Corporation). ２ O ３ The content of Al was determined by measuring the mass of Al using a fluorescent X-ray analyzer and then calculating the ratio of Al to the mass of the ceramic continuous fiber. ２ O ３ The mass of Al converted from SiO ２ The content was determined by measuring the mass of Si using a fluorescent X-ray analyzer and then calculating the ratio of SiO to the mass of the ceramic continuous fiber. ２ The mass may be calculated as the converted mass of Si. The measurement conditions are as follows:

[0077] Tube voltage: 30-50kV Tube current: 70-100mA Tube: Rh

[0078] In this embodiment, the ceramic continuous fiber may contain iron (Fe) derived from the raw materials. The mass ratio of iron to the mass of the ceramic continuous fiber (hereinafter also referred to as "Fe content") may be 3000 mass ppm or less, 1000 mass ppm or less, 500 mass ppm or less, or 100 mass ppm or less. The ceramic continuous fiber preferably does not contain iron (0 mass ppm), but the Fe content may be 0 mass ppm or more, more than 0 mass ppm, or 1 mass ppm or more. Furthermore, the Fe content may be more than 0 mass ppm and 3000 mass ppm or less, or 1 mass ppm or more and 500 mass ppm or less.

[0079] In this embodiment, the ceramic continuous fiber can be exemplified by at least one of a single fiber and a fiber bundle containing multiple single fibers, and a fiber bundle is preferable. In this embodiment, a "single fiber" means one independent fiber. Also, a "single fiber" may be an unbranched fiber.

[0080] In this embodiment, when the ceramic continuous fiber is a fiber bundle, the number of single fibers constituting the fiber bundle may be 10 or more, 20 or more, 50 or more, 90 or more, 100 or more, or 130 or more, and may be 100,000 or less, 50,000 or less, 10,000 or less, 5,000 or less, 3,000 or less, or 1,000 or less. Also, the number of single fibers constituting the fiber bundle may be 10 to 100,000, 20 to 5,000, 50 to 3,000, 50 to 1,000, 100 to 3,000, or 100 to 1,000.

[0081] In this embodiment, when the ceramic continuous fiber is a fiber bundle, the denier number can be 100,000 denier or less, 80,000 denier or less, 50,000 denier or less, or 30,000 denier or less. The denier number is an index indicating the thickness of the fiber bundle, and the larger the denier number, the thicker the fiber bundle. Furthermore, when the diameter of the single fibers constituting the fiber bundle is the same, the larger the denier number, the greater the number of single fibers constituting the fiber bundle. The lower limit of the denier number can be, for example, 500 denier or more, 700 denier or more, 900 denier or more, or 1,000 denier or more. Further, the range can be 500 denier to 100,000 denier or less, 700 denier to 80,000 denier or less, 900 denier to 50,000 denier or less, or 1,000 denier to 30,000 denier or less.

[0082] In this embodiment, the diameter of the single fiber may be 1 μm or more, 5 μm or more, 10 μm or more, or 15 μm or more, or may be 90 μm or less, 80 μm or less, or 70 μm or less. The diameter of the single fiber may also be 1 μm or more and 90 μm or less, 5 μm or more and 90 μm or less, 10 μm or more and 80 μm or less, or 15 μm or more and 70 μm or less. The diameter of the single fiber may be determined in the same manner as the filament diameter.

[0083] The ceramic continuous fibers may be made of either the same type of ceramic as the ceramic particles or a different type of ceramic.

[0084] (Organic Binder) The organic binder is used to mold the ceramic particles into a desired shape and to fix the ceramic particles around the ceramic continuous fiber. Examples of the organic binder include a resin, a wax, and a plasticizer, and further include a binder consisting of a resin, a wax, and a plasticizer.

[0085] In this embodiment, the resin contained in the organic binder can be freely selected within the scope of this embodiment, and is preferably a thermoplastic resin. Examples of the resin include polyolefin resins, aromatic polyether ketones, polyester resins, acrylic acid resins, polyamide resins, cellulose resins, polystyrene resins, polyvinyl chloride resins, polyvinyl alcohol resins, polyvinyl acetate resins, and polycarbonate resins, and at least one copolymer thereof. Examples of the resin include polyolefin resins, polyester resins, acrylic acid resins, polyamide resins, polystyrene resins, polyvinyl alcohol resins, and polyvinyl acetate resins, and at least one copolymer thereof. Examples of the resin include polyolefin resins, polyester resins, acrylic acid resins, polystyrene resins, polyvinyl alcohol resins, and polyvinyl acetate resins, and at least one copolymer thereof. Examples of the resin include polyolefin resins, polyester resins, acrylic acid resins, polystyrene resins, polyvinyl alcohol resins, and polyvinyl acetate resins, and at least one copolymer thereof. Examples of the resin include polyolefin resins, acrylic acid resins, polystyrene resins, and polyvinyl acetate resins, and at least one copolymer thereof. In this embodiment, the resin may be an acid-modified resin or a thermoplastic elastomer.

[0086] Examples of polyolefin resins include at least one homopolymer and copolymer containing one or more monomers selected from the group consisting of ethylene, propylene, 1-butene, 2-methylpropene, 1-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 1-octadecene. Specific examples of polyolefin resins include one or more selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-octene copolymer, polypropylene, propylene-1-butene copolymer, propylene-1-hexene copolymer, and polybutene, and one or more selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, polypropylene, propylene-1-butene copolymer, propylene-1-hexene copolymer, and polybutene are preferred.

[0087] As the polyolefin resin, one or more selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene are preferred, as this tends to reduce the production cost of the compound, and one or more selected from the group consisting of high-density polyethylene, low-density polyethylene, and polypropylene are more preferred.

[0088] Examples of polyester-based resins include at least one of ester-based resins obtained by polymerizing dicarboxylic acids and diols and ester-based resins obtained by polymerizing hydroxy acids. Specific examples of polyester-based resins include one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polylactic acid, polyhydroxybutyric acid, and polyglycolic acid.

[0089] As the polyester-based resin, one or more selected from the group consisting of polyethylene terephthalate, polybutylene naphthalate, and polylactic acid are preferred, as this tends to reduce the manufacturing cost of the compound, and at least one of polyethylene terephthalate and polylactic acid is more preferred.

[0090] Examples of aromatic polyether ketones include resins obtained from monomers containing a benzene ring in the main chain or derivatives thereof, and examples thereof include at least one of polyether ketone and polyether ether ketone.

[0091] Examples of acrylic acid-based resins include resins synthesized using one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, and derivatives thereof. Examples of the monomer include acrylic monomers having an alkyl group, acrylic monomers having an amino group, acrylic monomers having a hydroxy group, acrylic monomers having a carboxyl group, acrylic monomers having a cyano group, acrylic monomers having a glycidyl group, acrylic monomers having a vinyl ester bond, methacrylic monomers having an alkyl group, methacrylic monomers having an amino group, methacrylic monomers having a hydroxy group, methacrylic monomers having a carboxyl group, methacrylic monomers having a cyano group, methacrylic monomers having a glycidyl group, and methacrylic monomers having a vinyl ester bond.

[0092] Specific examples of the acrylic acid resin include one or more selected from the group consisting of polymethyl acrylate, polymethyl methacrylate, polyethyl acrylate, polyethyl methacrylate, polybutyl acrylate, polyhydroxyethyl acrylate, polyhydroxybutyl acrylate, polyacrylic acid, polymethacrylic acid, polymethacrylamide, polymethyl methacrylate, polybutyl methacrylate, poly2-ethylhexyl methacrylate, poly2-dimethylaminoethyl methacrylate, and poly2-hydroxyethyl methacrylate.

[0093] The acrylic acid resin is preferably one or more selected from the group consisting of polymethyl acrylate, polymethyl methacrylate, polyethyl acrylate, polyethyl methacrylate, polybutyl acrylate, polybutyl methacrylate, polyacrylic acid, and polymethacrylic acid, as this makes it easier for the ceramic particles to be dispersed in the compound.

[0094] Examples of polyamide resins include one or more selected from the group consisting of nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 6T, nylon 6I, nylon 9T, and nylon M5T.

[0095] The cellulose-based resin may be one or more selected from the group consisting of cellulose acetate, cellulose nitrate, and acetyl cellulose.

[0096] Examples of polystyrene resins include one or more selected from the group consisting of polystyrene, poly-α-methylstyrene, poly-o-methylstyrene, poly-p-methylstyrene, polyvinylxylene, polyethylstyrene, and polydimethylstyrene. At least one of polystyrene and poly-α-methylstyrene is preferred because it is easy to reduce the manufacturing cost of the compound.

[0097] Examples of the copolymer include one or more selected from the group consisting of ethylene-vinyl acetate copolymer, polyacrylonitrile-polybutadiene-polystyrene copolymer, polystyrene-butadiene copolymer, and ethylene-ethyl acrylate copolymer.

[0098] Examples of waxes contained in the organic binder include one or more selected from the group consisting of petroleum waxes, vegetable waxes, mineral waxes, fatty acids, and derivatives thereof.

[0099] Examples of the plasticizer contained in the organic binder include one or more selected from the group consisting of phthalic acid-based plasticizers, adipic acid-based plasticizers, and sebacic acid-based plasticizers.

[0100] The volume ratio of the ceramic particles to the total volume of the ceramic particles and the organic binder (hereinafter also referred to as "ceramic particle content") is 35% by volume or more, or 40% by volume or more, and 60% by volume or less, or 55% by volume or less. Examples of the ceramic particle content include 35% by volume or more and 60% by volume or less, or 40% by volume or more and 55% by volume or less. The ceramic particle content is the volume ratio of the ceramic particles to the volume of the compound at a temperature of 23°C.

[0101] When the filament contains an additive source, the mass ratio of the additive source to the total mass of the ceramic particles and the additive source is 0.3 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and 10.0 mass% or less, 9.0 mass% or less, or 8.0 mass% or less. Examples of the mass ratio include 0.3 mass% to 10.0 mass%; 0.5 mass% to 9.0 mass%; or 1.0 mass% to 8.0 mass%.

[0102] When the filament contains an additive source, the mass ratio of the additive source to the total mass of the ceramic particles, the organic binder, and the additive source is 0.2 mass% or more, 0.3 mass% or more, or 0.4 mass% or more, and 9.0 mass% or less, 8.5 mass% or less, or 8.0 mass% or less. Examples of the mass ratio include 0.2 mass% or more and 9.0 mass% or less, 0.3 mass% or more and 8.5 mass% or less, or 0.4 mass% or more and 8.0 mass% or less.

[0103] The compound of this embodiment has a flow initiation temperature of 20°C or higher, 25°C or higher, 30°C or higher, 50°C or higher, or 80°C or higher, and 300°C or lower, 280°C or lower, 250°C or lower, 200°C or lower, 180°C or lower, or 150°C or lower, and examples thereof include 20°C or higher and 280°C or lower, 25°C or higher and 280°C or lower, 50°C or higher and 200°C or lower, or 80°C or higher and 180°C or lower.

[0104] The flow initiation temperature is mainly affected by the type of resin, the type of wax, and the content of ceramic particles. For example, the flow initiation temperature tends to be higher when a resin synthesized from a monomer with a long main chain is used. The flow initiation temperature also tends to be higher when a resin with a high average molecular weight is used. The flow initiation temperature also tends to be higher when a wax with a high melting point is used. Furthermore, as the content of ceramic particles increases, the friction between the ceramic particles increases, so the flow initiation temperature tends to be higher. By adjusting these factors, the flow initiation temperature can be appropriately controlled.

[0105] The filament of this embodiment may be used for 3D printing.

[0106] <<Method for Producing Filaments>> The filament of this embodiment may be produced by any method as long as it has the above-described characteristics. A preferred method for producing the filament of this embodiment includes the following steps: bringing a resin composition containing ceramic particles and an organic binder, which has been heated at the following heating temperature, into contact with a ceramic continuous fiber; and: flow-start temperature of the resin composition (°C)≦heating temperature≦flow-start temperature of the resin composition (°C)+200°C. Passing the resin composition and the ceramic continuous fiber that have been in contact with each other through a spinning hole.

[0107] The filament manufacturing method of this embodiment can be carried out using, for example, the apparatus shown in FIG. 1 . A compound is introduced through a compound inlet 22. A ceramic continuous fiber 2 is supplied from a fiber supply unit 24 of a filament forming machine 20 in the conveying direction 6. The ceramic continuous fiber 2 is impregnated with the compound in a fiber impregnation unit 26 incorporating a cartridge heater 30, and is discharged through a spinning hole from a filament removal unit 28 having a spinning hole, thereby producing a filament 4. The filament 4 is transported to a winding machine 60 in the conveying direction 6 while being cooled by a blower 40. In the winding machine 60, the filament 4 passes through a roller 62 and is wound onto a bobbin 64.

[0108] The manufacturing method of this embodiment includes bringing a resin composition containing ceramic particles and an organic binder into contact with a ceramic continuous fiber, the resin composition having been heated at the following heating temperature: Flow starting temperature of the resin composition (°C)≦Heating temperature≦Flow starting temperature of the resin composition (°C)+200°C

[0109] By heating the compound at a temperature within this range, the compound is brought into a fluid state suitable for uniformly dispersing the compound around the ceramic continuous fibers.

[0110] For details of the ceramic particles and the organic binder, please refer to the above description of the filament of this embodiment.

[0111] In the manufacturing method of this embodiment, the resin composition may contain an additive source in addition to the ceramic particles and the organic binder. For details of the additive source, please refer to the above description of the filament of this embodiment.

[0112] In the manufacturing method of this embodiment, the heating temperature of the compound is preferably equal to or higher than the flow start temperature (°C) of the compound, equal to or higher than the flow start temperature (°C) of the compound + 10°C, equal to or higher than the flow start temperature (°C) of the compound + 30°C, or equal to or higher than the flow start temperature (°C) of the compound + 50°C, and equal to or lower than the flow start temperature (°C) of the compound + 200°C, equal to or lower than the flow start temperature (°C) of the compound + 180°C, equal to or lower than the flow start temperature (°C) of the compound + 170°C, or equal to or lower than the flow start temperature (°C) of the compound + 150°C. In addition, examples of the heating temperature of the compound include the following.

[0113] Compound flow start temperature (°C) + 10°C ≦ heating temperature ≦ compound flow start temperature (°C) + 180°C, or further, Compound flow start temperature (°C) + 30°C ≦ heating temperature ≦ compound flow start temperature (°C) + 170°C, or further, Compound flow start temperature (°C) + 50°C ≦ heating temperature ≦ compound flow start temperature (°C) + 150°C

[0114] A specific example of a method for heating the compound is to heat and knead the compound in the filament forming machine 20 shown in FIG.

[0115] The manufacturing method of this embodiment includes bringing the heated resin composition and the ceramic continuous fibers into contact with each other.

[0116] The contact method is arbitrary, and examples thereof include at least one of impregnating the continuous ceramic fibers with the compound in a fluid state and coating the continuous ceramic fibers with the compound in a fluid state.

[0117] Specific examples of the contact conditions include the following.

[0118] Contact atmosphere: Inert atmosphere or air atmosphere Contact temperature: Flow start temperature (°C) or higher, compound flow start temperature (°C) + 10°C or higher, compound flow start temperature (°C) + 30°C or higher, or compound flow start temperature (°C) + 50°C or higher, and compound flow start temperature (°C) + 200°C or lower, compound flow start temperature (°C) + 180°C or lower, compound flow start temperature (°C) + 170°C or lower, or compound flow start temperature (°C) + 150°C or lower

[0119] A specific example of the contact method is to impregnate the compound in a fluidized state with continuous ceramic fibers supplied from the fiber supply unit 24 in the fiber impregnation unit 26 in FIG.

[0120] The production method of this embodiment includes passing a resin composition and a ceramic continuous fiber (hereinafter also referred to as a "filament precursor") that have been brought into contact with each other through a spinning hole.

[0121] In the production method of this embodiment, the diameter of the spinning system is 5.0 mm or less, 4.0 mm or less, 3.0 mm or less, 2.0 mm or less, or 1.8 mm or less. In the production method of this embodiment, the diameter of the radiation hole is preferably less than 0.6 mm, 0.5 mm or less, or even 0.4 mm or less, because it is easier to prevent the compound from excessively covering the ceramic continuous fiber. The lower limit of the radiation hole diameter can be exemplified as more than 0.0 mm, 0.1 mm or more, or 0.2 mm or more. The diameter of the radiation hole can be more than 0.0 mm and 5.0 mm or less, 0.1 mm or more and 4.0 mm or less, 0.1 mm or more and 3.0 mm or less, 0.1 mm or more and 2.0 mm or less, 0.1 mm or more and 1.8 mm or less, 0.1 mm or more and less than 0.6 mm, 0.1 mm or more and 0.5 mm or less, or 0.2 mm or more and 0.4 mm or less.

[0122] Specific examples of the method for passing the resin composition and the ceramic continuous fiber that have been brought into contact with each other through the radiation hole include a method in which the diameter of the radiation hole in the filament take-out section 28 in FIG. 1 is 5.0 mm or less and the filament precursor is continuously discharged from the radiation hole, and a method in which the diameter of the radiation hole in the filament take-out section 28 in FIG. 1 is less than 0.6 mm and the filament precursor is continuously discharged from the radiation hole.

[0123] In addition, when the filament precursor is discharged from the radiation hole, the filament precursor is discharged from the radiation hole in a compressed state, and therefore, the compression of the filament after passing through the radiation hole is relaxed, and the diameter of the filament may become larger than the diameter of the radiation hole.

[0124] The manufacturing method of this embodiment may include cooling the filaments. The method for cooling the filaments is arbitrary, and examples thereof include at least one of liquid cooling and air blowing, with air blowing being preferred.

[0125] In this embodiment, the liquid cooling may be performed by immersing the filament in water at a temperature of 5° C. or higher and 60° C. or lower.

[0126] In the present embodiment, air cooling may be achieved by blowing air onto the filaments using a cooling fan. The rotation speed of the cooling fan may be, for example, 100 rpm or more, 200 rpm or more, or 300 rpm or more, and 3500 rpm or less, 3200 rpm or less, or 3000 rpm or less, and may be 200 rpm or more and 3500 rpm or more, or 300 rpm or more and 3000 rpm or more.

[0127] The manufacturing method of this embodiment may include winding the filament. The filament may be wound by any method, for example, by winding it on a bobbin. Winding the filament on a bobbin makes it easier to supply the filament to a 3D printing device.

[0128] In this embodiment, the winding speed when winding the film onto the bobbin may be 5 rpm or more, 8 rpm or more, or 10 rpm or more, and 30 rpm or less, 25 rpm or less, or 20 rpm or less. The winding speed may be 5 rpm or more and 30 rpm or less, or 10 rpm or more and 25 rpm or less.

[0129] The diameter of the bobbin may be 60 mm or more, 70 mm or more, or 80 mm or more, and 300 mm or less, 250 mm or less, or 200 mm or less. The diameter of the bobbin may be 60 mm or more and 300 mm or less, or 80 mm or more and 250 mm or less.

[0130] In this embodiment, the compound may be produced by any method. An example of a method for producing the compound is mixing ceramic particles and an organic binder and kneading the mixture under heat. Examples of kneading machines used for the kneading include one or more devices selected from the group consisting of a kneader, a Banbury mixer, an extruder, a high-speed mixer, and a roll. Conditions for the kneading are 100°C or higher, or 120°C or higher, and 220°C or lower, or 200°C or lower, and examples of the conditions ... or 200°C or lower.

[0131] <<Method for Producing Ceramic Matrix Composite Precursor>> Next, a method for producing a ceramic matrix composite precursor (hereinafter also referred to as a "CMC precursor") using the filament of this embodiment will be described.

[0132] The method for producing a CMC precursor using the filament of this embodiment includes heating the filament to melt the organic binder and then 3D printing the filament.

[0133] In this embodiment, a fused deposition modeling 3D printing device can be used as the 3D printing device for 3D printing. The fused deposition modeling 3D printing device may be a known device or have a known device configuration. For example, the 3D printing device may include a heating unit that heats the filament to melt the organic binder, a nozzle that ejects the filament with the molten organic binder, a bed, and a control unit.

[0134] The 3D printing device performs additive manufacturing by ejecting filaments, in which an organic binder is melted in a heating section, from a nozzle onto a bed, thereby obtaining a CMC precursor through 3D printing.

[0135] The control unit controls the spatial coordinates of the nozzle, the movement speed of the nozzle, and the amount of filament discharged from the nozzle.

[0136] In this embodiment, the temperature to which the filament is heated can be freely selected within a range that allows the filament to be 3D printed, and may be, for example, the flow initiation temperature of the compound used. The temperature to which the filament is heated is preferably at least the flow initiation temperature (°C) of the compound + 10°C, or at least the flow initiation temperature (°C) of the compound + 30°C, and is preferably at most the flow initiation temperature (°C) of the compound + 200°C, the flow initiation temperature (°C) of the compound + 180°C, the flow initiation temperature (°C) of the compound + 170°C, or the flow initiation temperature (°C) of the compound + 120°C. Examples of temperatures to which the filament is heated include the following:

[0137] Compound flow start temperature (°C) ≦ heating temperature ≦ compound flow start temperature (°C) + 200°C, Compound flow start temperature (°C) + 10°C ≦ heating temperature ≦ compound flow start temperature (°C) + 180°C, or further, Compound flow start temperature (°C) + 30°C ≦ heating temperature ≦ compound flow start temperature (°C) + 170°C, or further, Compound flow start temperature (°C) + 30°C ≦ heating temperature ≦ compound flow start temperature (°C) + 120°C

[0138] The nozzle temperature of the 3D printing device may be selected arbitrarily so as to be the above temperature.

[0139] In this embodiment, the path pitch is the distance between adjacent coplanar lines in fused deposition modeling 3D printing. The path pitch can be, for example, 0.3 times or more, 0.4 times or more, or 0.5 times or more the filament diameter, or 2.0 times or less, 1.5 times or less, or 1.3 times or less. Examples of the path pitch include 0.3 times or more and 2.0 times or less, 0.4 times or more and 1.5 times or less, or 0.5 times or more and 1.3 times or less the filament diameter.

[0140] (Ceramic Matrix Composite Material Precursor) The CMC precursor obtained using the filament of this embodiment (hereinafter also referred to as "the CMC precursor of this embodiment") contains ceramic particles, an organic binder, and ceramic continuous fibers.

[0141] The shape and size of the CMC precursor of this embodiment are not particularly limited.

[0142] <<Method for Producing Ceramic Matrix Composite Material>> A method for producing a ceramic matrix composite material using the CMC precursor of this embodiment will be described.

[0143] The CMC precursor of this embodiment can be calcined to produce a CMC exhibiting high tensile strength. The method of producing a CMC of this embodiment may include removing the organic binder from the CMC precursor prior to calcining the CMC precursor, or may further include removing the organic binder from the CMC precursor and calcining the CMC precursor prior to calcining the CMC precursor.

[0144] The method for producing a CMC of this embodiment may include removing the organic binder from the CMC precursor (hereinafter also referred to as a "debinding step") prior to firing the CMC precursor.

[0145] In the debinding step, the CMC precursor is heat-treated to obtain a debound body from which the organic binder has been removed. The debinding conditions may be any conditions that allow the organic binder to be burned off, and examples of the conditions include the following:

[0146] Degreasing atmosphere: oxidizing atmosphere or inert atmosphere, preferably air atmosphere Degreasing temperature: 300°C or higher, or 400°C or higher, and lower than 800°C or 700°C or lower

[0147] The debinding time may be changed as desired depending on the size of the CMC precursor and the characteristics of the debinding furnace used, and may be, for example, 30 minutes or more and 120 hours or less.

[0148] The method for producing a CMC according to the present embodiment may include calcining the CMC precursor to obtain a calcined body (hereinafter also referred to as a "calcination step") prior to firing the CMC precursor. When the method for producing a CMC according to the present embodiment includes a debinding step, the debound body may be subjected to calcination instead of the CMC precursor.

[0149] In the calcination step, the CMC precursor is calcined to obtain a calcined body. The calcination conditions may be any conditions that allow necking between ceramic particles to proceed, and examples of the conditions include the following:

[0150] Calcination atmosphere: oxidizing atmosphere or inert atmosphere, preferably air atmosphere Calcination temperature: 800°C or higher or 850°C or higher and lower than 1000°C or 900°C or lower

[0151] The calcination time may be changed as desired depending on the size of the CMC precursor (or degreased body) and the characteristics of the calcination furnace used, and may be, for example, from 30 minutes to 120 hours.

[0152] The method for producing a CMC of this embodiment includes calcining a CMC precursor (hereinafter also referred to as the "calcination step"). This results in the CMC of this embodiment. When the production method of this embodiment includes a degreasing step, the calcination can be performed by providing a degreased body instead of the CMC precursor, and when the calcination step includes a calcination step, the calcined body can be provided instead of the CMC precursor. The calcination can be performed under any conditions that allow sintering of the ceramic particles to proceed, and the following conditions can be given as calcination conditions.

[0153] Firing atmosphere: oxidizing atmosphere, inert atmosphere, preferably air atmosphere Firing temperature: 1000°C or higher, 1100°C or higher, or 1200°C or higher, and 1500°C or lower, 1450°C or lower, or 1400°C or lower Number of firings: 1 to 5 times

[0154] The firing time can be selected as desired depending on the size of the CMC precursor (or at least one of the degreased body and the calcined body) or the characteristics of the firing furnace used, and can be, for example, 30 minutes to 120 hours. When firing is performed multiple times, the firing atmosphere and firing temperature can be set to any desired conditions.

[0155] In the present embodiment, "atmospheric pressure firing" refers to a method of firing by heating without applying an external force to a material to be fired (e.g., a CMC precursor, a degreased body, a calcined body, etc.).

[0156] (Ceramic Matrix Composite Material) A CMC obtained using the filament of this embodiment (hereinafter also referred to as "CMC of this embodiment") will be described.

[0157] The CMC of this embodiment is a ceramic matrix composite material that includes a ceramic matrix and continuous ceramic fibers.

[0158] In the CMC of this embodiment, the ceramic matrix (specifically, the crystal particles constituting the matrix) is at least one of an oxide ceramic and a non-oxide ceramic, preferably an oxide ceramic, more preferably one or more selected from the group consisting of alumina, mullite, silica, and zirconia, even more preferably one or more selected from the group consisting of alumina, mullite, and zirconia, even more preferably at least one of alumina and mullite, and preferably contains at least alumina.

[0159] In the CMC of this embodiment, the ceramic continuous fiber is not particularly limited as long as it is a ceramic continuous fiber made of ceramic, and examples thereof include ceramic continuous fibers containing one or more selected from the group consisting of silicon carbide, alumina, and mullite, with ceramic continuous fibers containing at least one of alumina and mullite being preferred. Specific ceramic continuous fibers include one or more selected from the group consisting of silicon carbide continuous fibers, alumina continuous fibers, mullite continuous fibers, and alumina and mullite mixed continuous fibers, and further include at least one selected from the group consisting of alumina continuous fibers, mullite continuous fibers, and alumina and mullite mixed continuous fibers, and further include at least one of alumina continuous fibers and alumina and mullite mixed continuous fibers.

[0160] The CMC of this embodiment includes continuous ceramic fibers and a matrix, and may consist of continuous ceramic fibers and a matrix, but may also contain additives in addition to the continuous ceramic fibers and matrix.

[0161] It is sufficient that at least a portion of the additive is contained in the matrix, and it is preferable that the entire additive is contained in the matrix, which makes it easier to suppress grain growth of the crystal grains of the ceramic that constitutes the matrix during the production of the CMC of this embodiment.

[0162] The additive may be any compound having a different composition from the matrix. The additive may be, for example, one or more selected from the group consisting of silica, zirconia, yttria, ytterbium oxide, and mullite. Preferably, the additive is one or more selected from the group consisting of silica, zirconia, mullite, and ytterbium oxide, more preferably one or more selected from the group consisting of silica, zirconia, and mullite, or even more preferably silica and zirconia. The zirconia contained as the additive is zirconia in which yttrium is solid-dissolved, preferably Y ２ O ３ Zirconia in which yttrium is dissolved in a solid solution of 2.0 mol % or more and 4.0 mol % or less in terms of yttrium conversion, more preferably Y ２ O ３ It is sufficient if the zirconia contains 2.5 mol % or more and 3.5 mol % or less of yttrium in solid solution.

[0163] The CMC of this embodiment may contain 1 to 5 types of additives, 1 to 3 types of additives, 1 to 2 types of additives, or 1 type of additive.

[0164] In the CMC of this embodiment, the mass ratio of the additive (hereinafter also referred to as the "additive amount") to the total mass of the matrix, additive, and ceramic continuous fiber is 0.1 mass% or more, 0.2 mass% or more, or 0.3 mass% or more, and 8.5 mass% or less, 8.0 mass% or less, or 7.0 mass% or less. Examples of the additive amount are 0.1 mass% to 8.5 mass%, 0.2 mass% to 8.0 mass%, or 0.3 mass% to 7.0 mass%.

[0165] The CMC of this embodiment has a fiber volume fraction of 25% by volume or more, 35% by volume or more, or 40% by volume or more, and 60% by volume or less, 55% by volume or less, or 50% by volume or less. Examples of the fiber volume fraction include 25% by volume or more and 60% by volume or less, 35% by volume or more and 55% by volume or less, or 40% by volume or more and 55% by volume or less.

[0166] The CMC of this embodiment has a tensile strength A of 110 MPa or more, 120 MPa or more, 130 MPa or more, 150 MPa or more, 170 MPa or more, 180 MPa or more, 190 MPa or more, or 200 MPa or more, and 1000 MPa or less, 900 MPa or less, 850 MPa or less, 600 MPa or less, 500 MPa or less, 300 MPa or less, 280 MPa or less, or 250 MPa or less. Examples of the tensile strength A include 110 MPa or more and 1000 MPa or less, 120 MPa or more and 900 MPa or less, 130 MPa or more and 850 MPa or less, 150 MPa or more and 600 MPa or less, 150 MPa or more and 500 MPa or less, 170 MPa or more and 300 MPa or less, or 180 MPa or more and 250 MPa or less.

[0167] When the ceramic continuous fiber is an alumina continuous fiber, the CMC of this embodiment has a tensile strength A of 130 MPa or more, 150 MPa or more, or 170 MPa or more, and 1000 MPa or less, 900 MPa or less, or 850 MPa or less, for example, 130 MPa or more and 1000 MPa or less, 150 MPa or more and 900 MPa or less, or 170 MPa or more and 850 MPa or less. When the ceramic continuous fiber is a mixed continuous fiber of alumina and mullite, the CMC of this embodiment has a tensile strength A of 110 MPa or more, 120 MPa or more, 130 MPa or more, or 170 MPa or more, and 600 MPa or less, 500 MPa or less, 300 MPa or less, or 250 MPa or less, for example, 110 MPa or more and 600 MPa or less, 120 MPa or more and 500 MPa or less, 130 MPa or more and 300 MPa or less, or 170 MPa or more and 250 MPa or less.

[0168] The CMC of this embodiment has a tensile strength B of 110 MPa or more, 120 MPa or more, 130 MPa or more, 150 MPa or more, 170 MPa or more, 180 MPa or more, 190 MPa or more, or 200 MPa or more, and 1000 MPa or less, 900 MPa or less, 850 MPa or less, 600 MPa or less, 500 MPa or less, 300 MPa or less, 280 MPa or less, or 250 MPa or less. Examples of the tensile strength B include 110 MPa or more and 1000 MPa or less, 120 MPa or more and 900 MPa or less, 130 MPa or more and 850 MPa or less, 150 MPa or more and 600 MPa or less, 150 MPa or more and 500 MPa or less, 170 MPa or more and 300 MPa or less, or 180 MPa or more and 250 MPa or less.

[0169] When the ceramic continuous fiber is an alumina continuous fiber, the CMC of this embodiment has a tensile strength B of 130 MPa or more, 150 MPa or more, or 170 MPa or more, and 1000 MPa or less, 900 MPa or less, or 850 MPa or less, and examples thereof include 130 MPa or more and 1000 MPa or less, 150 MPa or more and 900 MPa or less, or 170 MPa or more and 850 MPa or less. When the ceramic continuous fiber is a mixed continuous fiber of alumina and mullite, the CMC of this embodiment has a tensile strength B of 110 MPa or more, 120 MPa or more, 130 MPa or more, or 170 MPa or more, and 600 MPa or less, 500 MPa or less, 300 MPa or less, or 250 MPa or less, for example, 110 MPa or more and 600 MPa or less, 120 MPa or more and 500 MPa or less, 130 MPa or more and 300 MPa or less, or 170 MPa or more and 250 MPa or less.

[0170] The CMC of this embodiment has a strength retention rate (hereinafter referred to as "strength retention rate") of 4.5±0.5 mm, which is the ratio of the tensile strength of a CMC having a crack with a length of 4.5±0.5 mm to the tensile strength of a CMC having no cracks. ｌ＝４．５±０．５ ") is, for example, 0.8 or more, or 0.9 or more, and 1.2 or less, or 1.1 or less. ｌ＝４．５±０．５ The fact that the strength retention rate is 0.8 or more means that even if the CMC has cracks in advance, the decrease in strength of the CMC is suppressed. ｌ＝４．５±０．５For example, the range may be 0.8 or more and 1.2 or less, or 0.9 or more and 1.2 or less.

[0171] Strength maintenance rate ｌ＝４．５±０．５ The tensile strength in the test piece may be a value determined by a method conforming to ASTM C1275 using a general strength testing machine (for example, MTS Criterion, manufactured by MTS Corporation) and a tensile testing jig, and the tensile strength may be determined by measuring the tensile strength twice at a loading rate of 0.5 mm / min and averaging the values ​​obtained.

[0172] Prior to the measurement, the measurement sample for measuring the tensile strength of a crack-free CMC may be a CMC processed to a width of 10±1 mm, a length of 100±10 mm, and a thickness of 1.2±0.6 mm.

[0173] Prior to the measurement, the measurement sample for measuring the tensile strength of a CMC having a crack may be a plate-shaped CMC processed into a shape such that the longitudinal length 500a is 100±10 mm, the longitudinal end width 500b is 19±1 mm, the crack lengths 500c and 500d are 4.5±0.5 mm, and the thickness is 1.2±0.6 mm, as shown in Figure 5. The width and thickness of the test piece may be measured with a micrometer, and the length of the test piece with a vernier caliper.

[0174] The CMC of this embodiment has a strength retention rate (hereinafter referred to as "strength retention rate") of 1.0 to 1.5 times the tensile strength of a CMC having a crack of 8.5±0.5 mm in length relative to the tensile strength of a CMC having no cracks. ｌ＝８．５±０．５ ") is, for example, 0.8 or more, or 0.9 or more, and 1.2 or less, or 1.1 or less. ｌ＝８．５±０．５ For example, the ratio may be 0.8 or more and 1.2 or less, or 0.9 or more and 1.1 or less.

[0175] Strength maintenance rate ｌ＝８．５±０．５ In the measurement sample for measuring the tensile strength of a cracked CMC, the length of the width 500b of the longitudinal end is 27±1 mm, and the lengths of the cracks 500c and 500d are 8.5±0.5 mm. ｌ＝４．５±０．５ can be found in a similar way.

[0176] The CMC of this embodiment has a breaking strain of 0.0030 or more, 0.0032 or more, or 0.0035 or more, and 0.0040 or less, 0.0038 or less, or 0.0037 or less. Examples of the breaking strain include 0.0030 or more and 0.0040 or less, 0.0032 or more and 0.0038 or less, or 0.0035 or more and 0.0037 or less.

[0177] The breaking strain may be determined as the strain at which the measurement sample breaks when a tensile strength test is conducted under the same measurement conditions as those for tensile strength A. The breaking strain may be measured by attaching a general strain gauge (e.g., KFG-2-120-C1-11L1M2R, manufactured by Kyowa Electric Industry Co., Ltd.) to the surface of the measurement sample using a general adhesive (e.g., CC-33A, manufactured by Kyowa Electric Industry Co., Ltd.).

[0178] The CMC of this embodiment has a Young's modulus of 60 GPa or more, 65 GPa or more, or 70 GPa or more, and 100 GPa or less, 95 GPa or less, or 90 GPa or less. Examples of the Young's modulus include 60 GPa or more and 100 GPa or less, 65 GPa or more and 95 GPa or less, or 70 GPa or more and 90 GPa or less.

[0179] Young's modulus can be calculated using the following formula: Young's modulus (GPa) = [{stress ０．０００５ (MPa) - stress ０．０００２ (MPa)} / {0.0005-0.0002}]×1 / 1000 In the above formula, stress ０．０００５ is the stress (MPa) when the strain is 0.0005, and stress ０．０００２ is the stress (MPa) when the strain is 0.0002. ０．０００５ and stress ０．０００２ can be determined from a stress-strain curve obtained by the same measuring method as for the breaking strain.

[0180] The CMC of this embodiment can be used for known CMC applications, and can be used for components containing the CMC, particularly for applications requiring heat resistance, such as heat-resistant structural materials, heat-resistant filters, turbine components, and nuclear power-related components. It can be used for one or more applications selected from the group consisting of:

[0181] The present disclosure will be described below with reference to examples, but the present disclosure is not limited to these examples.

[0182] In the examples and comparative examples, the average particle size, fiber content, void ratio, filament diameter, tensile strength, and flow initiation temperature were evaluated as follows.

[0183] (Average Particle Diameter) The average particle diameter was measured using a laser diffraction / scattering particle size distribution measuring device (device name: MT3300EX-II, manufactured by Microtrackbell) under the following conditions.

[0184] Light source: Semiconductor laser Voltage: 780mW Refractive index of alumina: 1.77 Refractive index of silica: 1.48 Refractive index of zirconia: 2.17 Refractive index of solvent (water): 1.333 Calculation mode: MT3000EXII

[0185] The measurement sample was prepared by dispersing particles in pure water after removing slow agglomerates by ultrasonic treatment to form a slurry.

[0186] (Filament Diameter) The filament diameter was determined by image analysis using a cross-sectional view of the filament obtained with a digital microscope (device name: VHX-6000, manufactured by Keyence Corporation) and image analysis software (product name: Nanohunter, manufactured by NanoSystems Corporation). The following measurement and analysis conditions were used.

[0187] Observation magnification: 200x or 300x Pixels: 1600 x 1200 pixels

[0188] Prior to the measurement, the filament was cut, embedded in resin so that the cut surface was exposed on the surface, and then polished using a manual polishing machine (device name: EcoMet 30, manufactured by Buhler) before use.

[0189] For image analysis, the cross-sectional observation image of the filament was imported into image analysis software, and the diameter of the circle equivalent to the area of ​​the outer periphery of the filament was taken as the filament diameter.

[0190] (Fiber Content) The fiber content was determined by performing image analysis using image analysis software (product name: Nanohunter, manufactured by NanoSystems) using a cross-sectional observation image of the filament prepared when determining the filament diameter.

[0191] For image analysis, the cross-sectional observation image of the filament was imported into image analysis software, and the diameter of the circle equivalent to the area of ​​the outer periphery of a single continuous ceramic fiber was taken as the diameter of the single continuous ceramic fiber. The number of single continuous ceramic fibers contained in the filament was also calculated using the image analysis software.

[0192] The fiber content was calculated using the filament diameter obtained by image analysis, the diameter of the single ceramic continuous fiber, and the number of single ceramic continuous fibers, according to the following formula.

[0193] Cross-sectional area of ​​the filament (μm ２ ) = {filament diameter (μm) / 2} ２ ×π Cross-sectional area of ​​ceramic continuous fiber (μm ２ ) = {diameter of single ceramic continuous fiber (μm) / 2} ２ × π × (number of single fibers of ceramic continuous fiber) Fiber content (area %) = Cross-sectional area of ​​ceramic continuous fiber (μm ２ ) / cross-sectional area of ​​filament (μm ２ ) x 100

[0194] (Porosity) The porosity was determined by performing image analysis using image analysis software (product name: Nanohunter, manufactured by NanoSystems) using the cross-sectional observation image of the filament prepared when determining the filament diameter.

[0195] First, the cross-sectional observation image of the filament was imported into image analysis software, and a circle equivalent to the area of ​​the outer periphery of the filament was created. Using the image analysis software, the circle equivalent to the area was converted into an 8-bit black and white image and converted into a grayscale image.

[0196] Next, the grayscale image was binarized using a threshold value of 110 to obtain a binary image. The obtained binary image was subjected to black-and-white inversion processing to obtain a processed image in which voids were white and filaments were black. Subsequently, noise in the processed image was removed using the hole filling function and isolated point removal function of the image processing software.

[0197] Next, using image analysis software, the area of ​​the white parts (void parts) in the obtained processed image was determined, and then the ratio (area %) of the area of ​​the white parts to the cross-sectional area of ​​the filament was calculated, and this value was taken as the void ratio.

[0198] (Tensile Strength A) Tensile strength A was measured using a strength tester (device name: AG-50kN Xplus, manufactured by Shimadzu Corporation) and a tensile test jig according to a method in accordance with JIS R 1656. The measurement was performed twice, and the average value was calculated. The CMC sample was processed to a width of 10±1 mm, length of 60±10 mm, and thickness of 1.2±0.6 mm, and epoxy glass tabs were attached to both ends to prepare a tensile test specimen. The width and thickness of the tensile test specimen were measured using a micrometer, and the length of the test specimen was measured using a vernier caliper. The loading rate was 1 mm / min.

[0199] (Tensile Strength B) Tensile strength B was determined using a strength tester (device name: MTS Criterion, manufactured by MTS) and a tensile test jig according to a method in accordance with ASTM C1275. The tensile strength was measured twice at a loading rate of 0.5 mm / min, and the average value of the values ​​obtained was taken as tensile strength B. The CMC sample was processed to a width of 10±1 mm, a length of 100±10 mm, and a thickness of 1.2±0.6 mm, and aluminum tabs were attached to both ends to prepare a tensile test specimen. The width and thickness of the tensile test specimen were measured using a micrometer, and the length of the test specimen was measured using a vernier caliper.

[0200] (Flow Initiation Temperature) The flow initiation temperature was determined using a thermal flow evaluation device (device name: CFT-500D, manufactured by Shimadzu Corporation) as the temperature at which the piston began to move from its position at the softening temperature. The measurement conditions are shown below.

[0201] Test temperature: 40°C to 250°C Heating rate: 5°C / min Applied pressure: 0.49 MPa Applied load: 5 kg Preheating time: 300 seconds Cylinder inner diameter: 11.3 mm (cross-sectional area: 1 cm ２ ) Piston outer diameter: 11.3mm (cross-sectional area: 1cm ２ ) Capillary die: A capillary die having a die with a cylindrical hole having a length of 1 mm and an inner diameter of 0.5 mm.

[0202] (Fiber volume fraction) Fiber volume fraction (V ｆ In the measurement of the cross-sectional observation of the CMC, a digital microscope (device name: VHX-6000, manufactured by Keyence Corporation) was used, and the image stitching function attached to the digital microscope was used to obtain the cross-sectional observation image under the following conditions: Observation magnification: 500 times Observation field: 20±1 mm × 9±1 mm

[0203] Prior to the measurement, the CMC samples were cut into square plates measuring 10±1 mm wide x 10±1 mm long, embedded in resin so that the cut surfaces were exposed to the surface, and then polished using a manual polishing machine (device name: EcoMet 30, manufactured by Buhler) to obtain measurement samples.

[0204] The cross-sectional observation image of the CMC was binarized using image analysis software (software name: Nanohunter, manufactured by Nanosystems), and the fiber volume fraction was determined by analyzing the resulting binarized image. The fiber volume fraction was calculated using the following formula, assuming that the white areas in the binarized image represent continuous ceramic fibers and the black areas in the binarized image represent the ceramic matrix. V ｆ = A ｆ / (A ｆ +A ｍ ) × 100 In the above formula, V ｆ is the fiber volume fraction (volume%), A ｆ is the area of ​​the ceramic continuous fiber (mm ２ ), A ｍ is the area of ​​the ceramic matrix (mm ２ )

[0205] (Strength maintenance rate ｌ＝４．５±０．５ and strength retention rateｌ＝８．５±０．５ ) Strength maintenance rate ｌ＝４．５±０．５ The tensile strength at 100°C was determined using a strength tester (device name: MTS Criterion, manufactured by MTS) and a tensile test jig according to a method in accordance with ASTM C1275. The tensile strength was measured twice at a loading rate of 0.5 mm / min and the average value was calculated. Prior to the measurement, the measurement sample for the tensile strength measurement of the crack-free CMC was processed to a width of 10 ± 1 mm, a length of 100 ± 10 mm, and a thickness of 1.2 ± 0.6 mm. Furthermore, the measurement sample for the tensile strength measurement of the cracked CMC was processed into a plate-shaped CMC with a longitudinal length 500a of 100 ± 10 mm, a longitudinal end width 500b of 19 ± 1 mm, crack lengths 500c and 500d of 4.5 ± 0.5 mm, and a thickness of 1.2 ± 0.6 mm, as shown in FIG. 5. The width and thickness of the test piece were measured with a micrometer, and the length of the test piece was measured with a vernier caliper.

[0206] Strength maintenance rate ｌ＝８．５±０．５ In the measurement sample for measuring the tensile strength of a cracked CMC, the length of the width 500b of the longitudinal end is 27±1 mm, and the lengths of the cracks 500c and 500d are 8.5±0.5 mm. ｌ＝４．５±０．５ was calculated in a similar manner.

[0207] (Fracture Strain) The fracture strain was determined as the strain at which the measurement sample broke when a tensile strength test was conducted under the same measurement conditions as for tensile strength A. The fracture strain was measured by attaching a strain gauge (device name: KFG-2-120-C1-11L1M2R, manufactured by Kyowa Electric Industry Co., Ltd.) to the surface of the measurement sample using an adhesive (product name: CC-33A, manufactured by Kyowa Electric Industry Co., Ltd.).

[0208] (Young's Modulus) Young's modulus was calculated using the following formula: Young's modulus (GPa) = [{stress ０．０００５ (MPa) - stress ０．０００２ (MPa)} / {0.0005-0.0002}]×1 / 1000 In the above formula, stress ０．０００５ is the stress (MPa) when the strain is 0.0005, and stress ０．０００２is the stress (MPa) when the strain is 0.0002. ０．０００５ and stress ０．０００２ was determined from the stress-strain curve obtained by the same measurement method as for the breaking strain.

[0209] Preparation of Compounds Synthesis Example 1 792 g of alumina powder (average particle size: 0.15 μm), 106 g of polybutyl methacrylate (product name: CB-1, manufactured by Sanyo Chemical Industries, Ltd.) as an organic binder, 52 g of ethylene-vinyl acetate copolymer (product name: Ultrathene 633, manufactured by Tosoh Corporation), 19 g of dibutyl phthalate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 98% or more) as a plasticizer, and 31 g of stearic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 95% or more) as a wax were added, and the mixture was heated and kneaded at 155 ° C. using a commercially available kneader (product name: Labo Kneader Mill TDR-3, manufactured by Toshin Co., Ltd.) to obtain a compound having an alumina powder content (ceramic particle content) of 50% by volume. This was designated as the compound of this synthesis example.

[0210] The compound of this example had a flow initiation temperature of 142°C.

[0211] Synthesis Example 2 Alumina powder (average particle size: 0.15 μm) was mixed with an acrylic resin as an organic binder, polystyrene, a plasticizer, and wax, and the mixture was heated and kneaded at 150° C. using a commercially available kneader (product name: Labo Kneader Mill TDR-3, manufactured by Toshin Corporation) to obtain a compound with an alumina powder content (ceramic particle content) of 50% by volume. This was designated as the compound of this Synthesis Example.

[0212] The compound of this synthesis example had a flow initiation temperature of 134°C.

[0213] (Synthesis Example 3) 796 g of alumina powder (average particle size: 0.15 μm), 115 g of polybutyl methacrylate (product name: CB-1, manufactured by Sanyo Chemical Industries, Ltd.) as an organic binder, 19 g of ethylene vinyl acetate copolymer (product name: Ultrathene 633, manufactured by Tosoh Corporation), 20 g of dibutyl phthalate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 98% or more) as a plasticizer, 18 g of paraffin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., melting point 68 to 70 ° C.) as a wax, and 38 g of stearic acid (manufactured by Fujifilm Wako Pure Chemical Industries, purity 95% or more) were added and heated and kneaded at 140 ° C. using a commercially available kneader (product name: Labo Kneader Mill TDR-3, manufactured by Toshin Co., Ltd.) to obtain a compound having an alumina powder content (ceramic particle content) of 50% by volume. This was the compound of this synthesis example.

[0214] The compound of this synthesis example had a flow initiation temperature of 172°C.

[0215] Synthesis Example 4 A compound having an alumina powder content (ceramic particle content) of 48 volume % was obtained in the same manner as in Synthesis Example 3, except that 796 g of alumina powder (average particle size: 0.15 μm) was replaced with 771 g of alumina powder (average particle size: 0.15 μm) as ceramic particles, 8 g of silica powder (average particle size: 0.24 μm) as additive sources, and 16 g of zirconia powder (average particle size: 0.02 μm). This compound was designated as the compound of this Synthesis Example. In addition, in the compound of this Synthesis Example, the mass ratio of the additive source to the total mass of the ceramic particles and additive source was 3.0 mass %, and the mass ratio of the additive source to the total mass of the ceramic particles, organic binder, and additive source was 2.4 mass %.

[0216] The compound of this synthesis example had a flow initiation temperature of 160°C.

[0217] <<Production of Filaments>> (Example 1) Using the filament production apparatus shown in Fig. 1, filaments were produced by the following method: 300 g of the compound obtained in Synthesis Example 2 was fluidized under the following conditions.

[0218] Heater temperature: 210°C Cartridge heater temperature: 210°C

[0219] Next, alumina and mullite mixed continuous fiber bundle (product name: Nextel 720 ceramic roving 1500 denier, manufactured by 3M Company, which has an α-alumina structure and a mullite structure, and ２ O ３ A ceramic continuous fiber having a content of 85% by mass (1500 denier, 400 single fibers) was impregnated with a fluid compound, and the alumina and mullite mixed continuous fiber bundle impregnated with the compound was formed into a thread through a spinning hole (spinning hole diameter: 0.4 mm). The heat was then removed by blowing air, and the fiber was wound around a polylactic acid bobbin at a winding speed of 16 rpm to obtain the filament of this example.

[0220] The filament production apparatus used here was a commercially available filament material production apparatus (product name: Filabot EX2, manufactured by Filabot) equipped with a fiber supply unit ("24" in FIG. 1) that supplies continuous ceramic fiber to the filament outlet, a fiber impregnation unit ("26" in FIG. 1) that impregnates the continuous ceramic fiber supplied from the fiber supply unit with a fluidized compound supplied from the filament material production apparatus, and a filament removal unit ("28" in FIG. 1) that discharges the continuous ceramic fiber impregnated with the compound. In addition, a commercially available cartridge heater (product name: TC-1NK, manufactured by AS ONE Corporation) was attached to the fiber impregnation unit of this filament production apparatus.

[0221] The filaments in this example were filaments containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, porosity, and filament diameter were as shown in Table 1 below.

[0222] (Example 2) A filament of this example was obtained in the same manner as in Example 1, except that the heater temperature of the filament manufacturing apparatus and the cartridge heater temperature were set to 230° C. The filament of this example was a filament containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, porosity, and filament diameter were as shown in Table 1 below.

[0223] (Example 3) A filament of this example was obtained in the same manner as in Example 1, except that the heater temperature of the filament manufacturing apparatus and the cartridge heater temperature were set to 250° C. The filament of this example was a filament containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, porosity, and filament diameter were as shown in Table 1 below.

[0224] (Example 4) A filament of this example was obtained in the same manner as in Example 1, except that the compound obtained in Synthesis Example 3 was used instead of the compound obtained in Synthesis Example 2, and the heater temperature and cartridge heater temperature of the filament manufacturing apparatus were set to 175° C. The filament of this example was a filament containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, porosity, and filament diameter were as shown in Table 1 below.

[0225] (Example 5) A filament of this example was obtained in the same manner as in Example 1, except that the compound obtained in Synthesis Example 4 was used instead of the compound obtained in Synthesis Example 2, and the heater temperature and cartridge heater temperature of the filament manufacturing apparatus were set to 175°C. The filament of this example was a filament containing alumina and mullite mixed continuous fibers, alumina particles (alumina powder particles), and silica powder particles and zirconia powder particles as additive sources, and had a fiber content, porosity, and filament diameter as shown in Table 1 below. The amount of additive source in the filament of this example was 1.5 mass%.

[0226] (Example 6) 600 g of the compound obtained in Synthesis Example 2 was used, the heater temperature of the filament manufacturing device and the cartridge heater temperature were set to 230°C, and an alumina and mullite mixed continuous fiber bundle (product name: Nextel 720 Ceramic Roving 10,000 denier, manufactured by 3M Company, having a crystal structure of α-alumina structure and mullite structure, and Al ２ O ３ The filament of this example was obtained in the same manner as in Example 1, except that three ceramic continuous fibers (10,000 denier, 2,550 single fibers) were bundled and impregnated with a fluidized compound, and the diameter of the spinning hole of the filament manufacturing apparatus was 1.8 mm. The filament of this example was a filament containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, porosity, and filament diameter were as shown in Table 1 below.

[0227] (Comparative Example 1) A filament of this comparative example was obtained in the same manner as in Example 1, except that the diameter of the spinning hole in the filament take-out section of the filament manufacturing apparatus was set to 0.6 mm. The filament of this comparative example was a filament containing alumina and mullite mixed continuous fibers and alumina particles (alumina powder particles), and the fiber content, void ratio, and filament diameter were as shown in Table 1 below.

[0228] <Evaluation of Filament Cracks> The number of cracks in the filament compound was evaluated for the Examples and Comparative Examples. The number of cracks was calculated as the number of cracks per meter of filament. The evaluation results are shown in Table 1 below.

[0229] Table 1 below shows the preparation conditions and evaluation results of the examples and comparative examples.

[0230]

[0231] The filaments of the examples all had a fiber content of 15 area % or more. Furthermore, the porosity of the filaments of the examples was less than 19 area %, confirming that the porosity was small. From Examples 1 to 3, it was confirmed that increasing the heater temperature of the filament manufacturing device and the cartridge heater temperature increased the fiber content. Furthermore, as shown in Figure 2, it was confirmed that the ceramic continuous fiber of the filament of Example 2 was coated with the compound.

[0232] As shown in Table 1, by comparing the Examples and Comparative Examples, it was confirmed that the filaments of Examples 1 to 6, which had a fiber content of 15% by area or more, had fewer cracks in the compound.

[0233] Specifically, as shown in Figure 3, it can be seen that the filament of Example 2 has very few cracks in the compound. On the other hand, it can be seen that the filament of Comparative Example 1 has many cracks in the compound, as shown by the solid circle in Figure 4. Furthermore, as shown by the dashed circle in Figure 4, the filament of Comparative Example 1 had some areas where the compound had peeled off from the continuous ceramic fiber, exposing the continuous ceramic fiber.

[0234] <<Production of CMC precursor by 3D printing>> (Example 7) Using a commercially available 3D printing device (product name: Original Prusa i3 MK3S, Prusa Research), the CMC precursor of this example was produced using the filament of Example 2.

[0235] Specifically, first, the organic binder contained in the filament of Example 2 was melted under the following conditions.

[0236] Nozzle temperature: 180°C

[0237] Next, the filament of Example 2 with the molten organic binder was 3D printed under the following conditions to obtain a CMC precursor of this example, with dimensions per layer of 120±10 mm length and 150±10 mm width.

[0238] Bed temperature: 120°C Printing speed: 7.5 mm / s Pass pitch: 0.4 mm Lamination pitch: 0.2 mm Number of layers: 3

[0239] Example 8 A CMC precursor of this example was produced in the same manner as in Example 7, except that the filaments of Example 1 were used instead of the filaments of Example 2.

[0240] Example 9 A CMC precursor of this example was produced in the same manner as in Example 7, except that the filaments of Example 3 were used instead of the filaments of Example 2.

[0241] Example 10 A CMC precursor of this example was produced in the same manner as in Example 7, except that the filaments of Example 4 were used instead of the filaments of Example 2.

[0242] Example 11 A CMC precursor of this example was produced in the same manner as in Example 7, except that the filaments of Example 5 were used instead of the filaments of Example 2.

[0243] Example 12 A CMC precursor of this example was produced in the same manner as in Example 7, except that the path pitch was set to 0.3 mm.

[0244] Example 13 A CMC precursor of this example was produced in the same manner as in Example 7, except that the path pitch was set to 0.5 mm.

[0245] Comparative Example 2 A CMC precursor of this comparative example was produced in the same manner as in Example 7, except that the filaments of Comparative Example 1 were used instead of the filaments of Example 2.

[0246] <<Preparation of CMC>> (Example 14) The CMC precursor obtained in Example 7 was heat-treated in an air atmosphere at 450°C, and then heat-treated at 900°C to form a calcined body. This calcined body was heat-treated in an air atmosphere at 1100°C, and then cooled to room temperature to obtain the CMC of this example.

[0247] The CMC of this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as a matrix, and had a tensile strength A of 256 MPa. This confirmed that the CMC produced by 3D printing using the filament of this example exhibited high tensile strength.

[0248] (Example 15) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 8 was used instead of the CMC precursor of Example 7.

[0249] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0250] (Example 16) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 9 was used instead of the CMC precursor of Example 7.

[0251] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0252] (Example 17) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 10 was used instead of the CMC precursor of Example 7.

[0253] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0254] (Example 18) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 11 was used instead of the CMC precursor of Example 7.

[0255] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers, alumina as the matrix, and silica and zirconia as additives.

[0256] (Example 19) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 12 was used instead of the CMC precursor of Example 7.

[0257] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0258] (Example 20) The CMC of this example was obtained in the same manner as in Example 14, except that the CMC precursor of Example 13 was used instead of the CMC precursor of Example 7.

[0259] The CMC in this example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0260] Comparative Example 3 The CMC of this comparative example was obtained in the same manner as in Example 14, except that the CMC precursor of Comparative Example 2 was used instead of the CMC precursor of Example 7.

[0261] The CMC of this comparative example was a CMC containing alumina and mullite mixed continuous fibers and alumina as the matrix.

[0262] Tables 2 and 3 below show the preparation conditions and evaluation results of the examples and comparative examples.

[0263]

[0264]

[0265] As is clear from Table 2 above, by comparing the Examples and Comparative Examples, it was confirmed that the CMC obtained using filaments with a fiber content of 15 area % or more had a tensile strength A of 110 MPa or more, which was higher than that of the Comparative Examples.

[0266] In Example 14, the tensile strength B was 227 MPa. ｌ＝４．５±０．５ and strength retention rate ｌ＝８．５±０．５ were 1.1 and 1.0, respectively, and it was confirmed that even if the length of the crack in the CMC having a crack is increased, the decrease in the strength of the CMC is suppressed.

[0267] As is clear from Table 3 above, by comparing Examples 14, 19, and 20, it was confirmed that the tensile strength A of the resulting CMC was the largest when a CMC precursor obtained with a path pitch of 0.4 mm was used.

[0268] The entire contents of the specification, claims, abstract and drawings of Japanese Patent Application No. 2024-150095, filed on August 30, 2024, are hereby incorporated by reference as the disclosure of the specification of the present disclosure.

[0269] 2 Ceramic continuous fiber 4 Filament 6 Direction of conveyance of ceramic continuous fiber and filament 20 Filament forming machine 22 Compound inlet 24 Fiber supply section 26 Fiber impregnation section 28 Filament take-out section 30 Cartridge heater 40 Blower 60 Winder 62 Roller 64 Bobbin 100 Filament manufacturing device 500 External view showing a test piece used to measure the tensile strength of a CMC having a crack at the strength retention rate 500a Length in the longitudinal direction 500b Width of end in the longitudinal direction 500c Length of the crack 500d Length of the crack

Claims

1. A filament comprising ceramic particles, an organic binder, and continuous ceramic fibers, wherein the area ratio of the cross-sectional area of ​​the continuous ceramic fibers to the cross-sectional area of ​​the filament is 15 area % or more.

2. The filament according to claim 1, wherein the ceramic particles are one or more selected from the group consisting of alumina particles, mullite particles, silica particles, and zirconia particles.

3. The filament according to claim 1 or 2, wherein the ceramic continuous fiber is one or more selected from the group consisting of alumina continuous fiber, mullite continuous fiber, and alumina and mullite mixed continuous fiber.

4. The ceramic continuous fiber has an α-alumina structure and a mullite structure, and Al ２ O ３ The filament according to claim 1 , wherein the content is 80% by mass or more and less than 100% by mass.

5. A filament according to any one of claims 1 to 4, wherein the area ratio of the cross-sectional area of ​​the void portion to the cross-sectional area of ​​the filament is less than 19 area %.

6. A filament according to any one of claims 1 to 5, wherein the volume ratio of the ceramic particles to the total volume of the ceramic particles and the organic binder is 35 volume % or more and 60 volume % or less.

7. A filament according to any one of claims 1 to 6, wherein the ceramic continuous fiber is composed of 100 or more single fibers.

8. The filament according to any one of claims 1 to 7, which is for use in 3D printing.

9. A method for producing a filament according to any one of claims 1 to 8, comprising: bringing a resin composition containing the ceramic particles and the organic binder, which has been heated at the following heating temperature, into contact with the ceramic continuous fiber; and passing the resin composition and the ceramic continuous fiber that have been brought into contact with each other through a spinning hole.

10. The method of claim 9, wherein the diameter of the spinning holes is less than 0.6 mm.

11. A method for producing a ceramic matrix composite precursor, comprising heating the filament according to any one of claims 1 to 8 to melt an organic binder, and then 3D printing the filament.

12. A method for producing a ceramic matrix composite material, comprising firing the ceramic matrix composite precursor obtained by the method of claim 11.

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